The invention relates to a method for mixing at least two liquid components of different viscosities of a multi-component material, such as a tissue adhesive, during application thereof, the components being pressed out of separate containers, mixed, and applied by aid of an application part, e.g. a cannula.
Furthermore, the invention also relates to a device for mixing at least two liquid components of different viscosities of a multi-component material, such as a tissue adhesive, during application thereof, said device comprising separate component entrances provided in spaced relationship from each other, a mixing region, and an exit.
From AT 379 311 B, a device for applying a tissue adhesive is known in which the two components of the tissue adhesive, i.e. thrombin, on the one hand, and fibrinogen, on the other hand (or, strictly speaking, solutions thereof), by means of a double-syringe reach a device designed as a one-piece collecting head or connecting head, where the two components are supplied to a mixing cannula, or a mixing catheter via separate channels, together with a gas used for mixing. In the mixing cannula, or mixing catheter, respectively, thus the two components are mixed if required; in doing so, the gas is continuously supplied so as to keep clear the individual conveying channels whenever the tissue adhesive components are not being supplied.
A device for applying a multi-component tissue adhesive which is similar as regards mixing of the components by using a gas furthermore is known from EP 669 100 A, that device being provided for spray application of the tissue adhesive. To this end, the components are mixed immediately downstream of the front side of the connecting body designed with various channels, and atomized by aid of a medicinal gas.
In contrast to these known devices, more and more often a mixture of the components without the assistance of a medicinal gas is desired. Thorough mixing of the components without an early clot formation causing blocking of the passages poses substantial problems. From U.S. Pat. No. 5,116,315 A, a double syringe is known which has a connecting head having entrances connected to the delivery ends of the syringes and having a forward end side facing away from the syringes provided with a conical spray top latchingly engaging with the connecting body and in which a flat, disk-shaped mixing space is formed into which the conveying channels for the tissue adhesive components end at the outer periphery thereof, and from which centrally an axial exit leads away. On this top, a cannula, e.g., can be put. The design of this device may allow formation of clot within the device which would lead to clogging.
It is now an object of the invention to eliminate these problems and to provide a method and an arrangement, respectively, of the initially defined kind with which a reliable mixing of the components of a multi-component material is obtained without premature solidification, wherein also the supply of a medicinal gas is no longer necessary.
The method according to the present invention is characterized in that the less viscous component is directly pressed into the jet or flow of at least one other component having a higher viscosity.
In corresponding manner, the device of the present invention is characterized in that the entrance for the less viscous component is followed by a guiding part for pressing the less viscous component directly into a flow passage for the more viscous component, which flow passage leads from the entrance to the exit.
According to the present invention, thus, the less viscous component is actively pressed into the other, more viscous component, e.g. by injecting a jet of the less viscous component directly into the jet or flow of the more viscous component. This ensures good mixing of the two components, the more viscous component being entrained by the less viscous componentxe2x80x94which preferably is pressed in at an approximately right angle to the flow direction of the more viscous component. Since subsequently the component jet or flow may immediately be supplied to the exit or to the applicator tip respectively, with dead spaces being avoidable without any problem, undesired clot formation is avoided. Before the less viscous component is pressed into the jet or flow of the more viscous component, the less viscous component may deliberately be delayed so that the two components will arrive practically simultaneously in the mixing region despite the higher flow rate of the less viscous component due to its lower viscosity. This delay could as such be attained by a delayed supply of the component to the entrance, e.g. by a delayed pressing out of a syringe body as compared to the other, more viscous component. As regards the device itself, an embodiment of the device according to the invention which is particularly advantageous as regards such a delay is characterized in that the guiding part simultaneously defines a delaying path for the less viscous component. Here, the guiding part will guide the less viscous component on a longer path, the delaying path, as far as to the flow passage for the highly viscous component, i.e. the flow paths for the different components of the multi-component material are differently configured.
In connection with the delay of the less viscous component, it may also be suitable if the entrance for the less viscous component has a smaller passage cross-section than the entrance for the more viscous component. Namely, if the piston paths from the commonly used syringe bodies are equal at a simultaneous actuation of the syringe pistons and corresponding component amounts are pressed out, by the narrowing of the entry channel for the less viscous component, i.e. the smaller passage cross-section, a higher velocity and thus energy of the less viscous component can be attained so that the latter, despite a longer flow time caused by the delay on or in the guiding part, respectively, nevertheless will enter into the jet or flow of the highly viscous component with a sufficiently high energy so as to ensure thorough mixing.
Preferably, the less viscous component is delayed as mentioned before, by being detoured, or deflected, respectively, so as to compensate the lower flow velocity of the other component given on account of its higher viscosity. Preferably, the jet of the less viscous component can be deflected on a guiding surface or impacting surface for the purpose of retarding it. In doing so, the jet of the less viscous component impacts on the guiding or impacting surface and is deflected by the latter to the preferably substantially straight-line jet or flow of the more viscous component.
On the other hand, however, it is also possible to attain the delay by pressing the jet of the less viscous component into a blind tube arranged adjacent the jet or flow of the more viscous component and having at least one lateral nozzle opening at a distance from the forward, closed end face and through at least one lateral nozzle opening into the jet or flow of the more viscous component. The less viscous component enters the blind tube, passes as far as to the closed forward end face and only then emerges through at least one lateral nozzle opening so as to get into the jet or flow of the more viscous component. By the length of the blind portion of the tube, i.e. the distance of the nozzle opening(s) from the forward, closed end face, the time of the delay can be fixed.
An advantageous embodiment of the device according to the invention is characterized in that the guiding part defines an angularly arranged, optionally curved guiding face for deflecting the jet of the less viscous component towards the flow passage for the more viscous component. On the other hand, in terms of construction, it may advantageously be provided that a blind tube is provided as a guide part adjacent the flow passage for the more viscous component, which blind tube, at a distance from its forward, closed end face, has at least one nozzle opening ending in the flow passage for the more viscous component, the blind tube being connected with the inlet for the less viscous component. The flow passage for the more viscous component may also be formed by a cannula or a cannula holder, by a flexible tube or also by a channel in a connecting head.
The device according to the present invention may advantageously comprise a one-piece collecting or connecting head with a connecting part for a cannula or a catheter, in particular a double lumen catheter, the guiding part being provided in the region of the connecting part. For a simple production it is particularly advantageous if the guiding face is moulded to the forward end face of the connecting head and opens towards the mixing region which is outwardly delimited by a cannula holder slipped thereto. For completing the application device, preferably the entrances of the device moreover are connected with discharge parts of syringe bodies; in this case, the syringe bodies contain the different components of the multi-component material.